Candidate evaluation

With a selection of audiological tests, you can identify when Baha® is the best solution for your patient. The patient can also wear a testband to try Baha before deciding on implantation.

The Baha® System works independently of the severity of the conductive part of the hearing loss as it bypasses the outer and middle ear. The bone conduction threshold is therefore the most relevant measurement in the audiological assessment. Use the candidate’s air-bone gap and bone conduction thresholds as a guide to the benefits that can be anticipated from choosing Baha instead of an air conduction hearing aid. Comparing the results of functional gain measurements in free field testing, with and without the sound processor, will also be useful.

Candidates with an air-bone gap of more than 30 dB are good candidates for Baha.1-5 In mixed losses the sensorineural component should be no greater than 65 dB.

Suggested audiological evaluations for adults

  • Pure tone audiometry (average bone thresholds at 500, 1000, 2000 and 3000 Hz)
  • Bone conduction thresholds (500, 1000, 2000 and 3000 or the PTA value)
  • Speech audiometry (e.g. HINT/QuikSin testing, maximum speech intelligibility test)
  • Free field testing* (Baha sound processor on a testband or test rod, or a Baha Softband and sound presented through loud speakers)
  • Aided and unaided speech test in noise (Baha sound processor on a testband or test rod, or a Baha Softband, speech and noise presented through loud speakers)

Free field testing

Let the patient wear the sound processor on a testband/Baha Softband to determine the benefit. It is recommended that you use a more powerful sound processor for this test in order to better reflect the aided thresholds on an implant, since the skin will lessen the signal of the Baha by 10-15 dB.

Candidates with SSD

For patients with SSD, we recommend letting the candidate evaluate the benefit in situations where they normally struggle. Let the candidate borrow a sound processor and a Baha Softband or headband and instruct them to evaluate the benefits in their daily life. This test should be performed with a more powerful sound processor to compensate for the percutaneous fitting.

References

  1. Hol MK, Snik AF, Mylanus EA, Cremers CW. Long-term results of bone-anchored hearing aid recipients who had previously used airconduction hearing aids. Archives of Otolaryngology-Head & Neck Surgery 2005;131(4):321-5.
  2. McDermott AL, Dutt SN, Reid AP, Proops DW. An intra-individual comparison of the previous conventional hearing aid with the boneanchored hearing aid: The Nijmegen group questionnaire. The Journal of Laryngology and Otology 2002(28):15-9.
  3. Mylanus EA, Snik AF, Cremers CW. Patients’ opinions of boneanchored vs conventional hearing aids. Archives of Otolaryngology-Head & Neck Surgery 1995;121(4):421-5.
  4. Mylanus EA, van der Pouw KC, Snik AF, Cremers CW. Intraindividual comparison of the bone-anchored hearing aid and air-conduction hearing aids. Archives of Otolaryngology-Head & Neck Surgery 1998;124(3):271-6.
  5. Flynn MC, Sadeghi A, Halvarsson G. Baha solutions for patients with severe mixed hearing loss. Cochlear Implants Int 2009;10 Suppl 1:43-7.